In the popular imagination, there are two types of farming: rural farming in wide open spaces, and city farming on rooftop gardens and in various little nooks and crannies. The rural farmers obviously provide more food, right? The truth isn’t quite so simple, especially in developing countries.
According to a new study that uses NASA’s satellite imagery, about 1.1 billion acres of land in and around cities is being used for food cultivation. That’s like having an urban farming community the size of the European Union. Zooming into the urban core, there are 166 million acres of land used to grow crops.
Most of the world’s urban farms don’t produce cereals like rice and wheat; instead, the grow perishable crops like fresh vegetables. This should be no surprise to anyone who’s been to an urban farm in a city like San Francisco that grows its crops more for pleasure than necessity, but it turns out to be true the world over.
The study, conducted by the International Water Management Institute, the University of California-Berkeley, and Stanford University, also examined water use in urban agriculture. Much of the world’s farmed urban land is rain fed, but a significant portion is under irrigation, which allows farmers to grow vegetable in the dry season, but also risks exposing residents to contaminants found in drinking water.
In Accra, Ghana, for example, the city’s 2,000 urban farmers provide food for 800,000 residents–much of it irrigated with recycled (and polluted) household wastewater. This doesn’t mean that water shouldn’t be recycled; cities just need to use more responsible methods to do so.